1. Field of the Invention
The present invention relates to an angular lens barrel used in an optical device such as a camera.
2. Related Background Art
Conventionally, as lens barrels in optical devices such as cameras, lens barrels having rectangular cross sections are known as disclosed in Japanese Patent Utility Model No. 2548509 and Japanese Patent Laid-Open No. 9-222550. These lens barrels cannot extend and retract in the same manner as in a cylindrical lens barrel that extends and retracts upon being rotated by a helicoid mechanism. For this reason, a link mechanism is placed in a lens barrel, and the lens barrel extends and retracts along the optical axis upon extension/contraction of the link mechanism.
According to the lens barrel disclosed in each reference described above, the link mechanism serves not only as a driving mechanism for applying extending force and retracting force to the lens barrel but also as a guide mechanism for moving the lens barrel along the optical axis. For this reason, the link mechanism needs to have certain rigidity, and link pieces and the like making up the link mechanism must be thick. As a consequence, the link mechanism becomes considerably thick as a whole, resulting in an increase in the size of the lens barrel
In addition, to make the link mechanism serve as a guide mechanism, the link mechanism and associated peripheral structures must be accurately formed.